one two three four
one two three four .
o̞ n e̞ WORD_BOUNDARY t̪̻ w o̞ WORD_BOUNDARY t̪̻ x r e̞ e̞ WORD_BOUNDARY f o̞ u r WORD_BOUNDARY
o n e WORD_BOUNDARY t w o WORD_BOUNDARY t h r e e WORD_BOUNDARY f o u r WORD_BOUNDARY . WORD_BOUNDARY